Citation
Abstract
This report presents a concentrated overview of the critical issues and tools for the development of real-time systems. Real-time systems are defined to be those which perform their actions in response to stimuli from outside themselves, and which must respond to these stimuli within fixed, predetermined time limits. A real-time system with many independent external stimuli almost certainly contains a large number of interacting asynchronous processes. From the viewpoint of the equipment surrounding this real-time system, these processes operate in parallel, and their operations are only partially ordered. A single process can be well represented by a flow chart which relates step-by-step exactly which action follows the last one. Multiple interacting asynchronous processes cannot be conveniently described by a flow chart of their combined operations, even though when taken individually each process can be depicted on a flow chart. However, each of the multiple asynchronous processes can be readily understood as a finite state machine, and the interaction between machines can be graphically represented by a state-transition net, or ‘‘Petrinet.’ This report develops the use of such nets for software and hardware design through description and example.
Details
- Volume
- 42-28
- Published
- August 15, 1975
- Pages
- 57–68
- File Size
- 1.4 MB